CVD is a disorder that affects the heart's ability to function normally. The most common cause of heart disease is narrowing or blockage of the coronary arteries, which supply blood to the heart. There are many risk factors for CVD, including inflammation, high blood pressure, high cholesterol, and obesity. Small quantities of trace elements, also known as micronutrients, are essential in maintaining a healthy body. Research has shown that some trace elements may be associated with the development of CVD, but more research is needed to confirm this connection. This study will examine concentrations of several trace elements in toenail samples of young adults participating in the Coronary Artery Risk Development in Young Adults (CARDIA) study. The CARDIA study is measuring changes in CVD risk factors in individuals as they age and is identifying lifestyle habits that influence those changes. The purpose of this study is to determine the link between trace elements and CVD risk factors in young adults. The results of this study may help to identify whether dietary, lifestyle, or environmental factors can be modified at a young age to prevent the development of CVD.